A polysaccharide derivative obtained by modifying the hydroxyl groups or amino groups of a polysaccharide with various types of substituents is known to serve as a chiral stationary phase in chromatography to show a high optical resolution, and a large number of kinds of polysaccharide derivatives have been heretofore synthesized.
As such a polysaccharide derivative useful as a separating agent for optical isomers, for example, a polysaccharide derivative that contains a structure in which hydroxyl groups or amino groups at 2-position and 3-position (and 6-position) of the polysaccharide are substituted with different specific substituents is proposed (see Patent Document 1). As another polysaccharide derivative useful as a separating agent for optical isomers, a polysaccharide derivative is proposed in which hydroxyl groups or amino groups of the polysaccharide are substituted with two or more different specific kinds of substituents, and particularly a substituent at the 2-position and 3-position and a substituent at the 6-position are different from each other (see Patent Document 2).